An Effective Water Body Extraction Method with New Water Index for Sentinel-2 Imagery

Surface water bodies, such as rivers, lakes, and reservoirs, play an irreplaceable role in global ecosystems climate systems. Sentinel-2 imagery provides new high-resolution satellite remote sensing data. Based on the analysis of spectral characteristics satellite, a novel index called (SWI) that is based vegetation-sensitive red-edge band (Band 5) shortwave infrared 11) bands was developed. Four representative body types, namely, Taihu Lake, Yangtze River, Chaka Salt Chain were selected study areas to conduct extraction performance comparison with normalized difference (NDWI). We found (1) contrast value SWI larger than NDWI terms various including purer water, turbid salt floating ice, which suggested could achieve better enhancement for bodies. (2) An effective method proposed by integrating Otsu algorithm, accurately extract types high overall accuracy. (3) The effectively extracted large bodies wide river channels suppressing shadow noise urban areas. Our results can efficient rapidly extracting from data has application potential larger-scale surface mapping.